These are 1-1/2" tall by 8" long DUCATI gold on a clear background gas petrol tank waterslide decals and they are sold in pairs. This open letter type logo came on 1975-85 models. These were originally made by a decal company for Bob Miller Specialties in Connecticut to use on the 900 Super Sport with shiny black gas tank from about 1980 or 1981. 

My name is Tony Schanz, I formerly ran DomiRacer Distributors in Cincinnati, Ohio buying and selling vintage English, Italian, & German motorcycle parts, tools, accessories & memorabilia. DomiRacer closed 6/11/2013, but I still deal in parts, motorbikes, decals, advertising, photos, posters, & more. Please add my store, The Real DomiRacer, to your favorite sellers and watch for other rarities in my future eBay listings.